Minocycline has been licensed for over 35 years for a wide range of bacterial infections (a Summary of Product Characteristics [SPC] lists 16 indications) including respiratory, genitourinary and skin conditions.1,2 However, much of its popularity has been for its use in treating acne. Minocycline was associated with claims that it was “more effective, less likely to cause bacterial resistance and easier to take than other tetracyclines”.3 In addition, the availability of an adherence-friendly, once-daily, modified-release preparation and a lack of restriction when taken with food or ‘moderate amounts of milk’, quickly made it a favourite with general practitioners and patients. It became particularly popular for use for teenagers with acne, a group notorious for non-adherence and for whom a single daily dose was seen as an advantage. Between 1997 and 2006 about 500,000 prescriptions for minocycline were dispensed each year in England, accounting for about one third of all tetracycline prescriptions by volume and two thirds by cost.4 Partly as a result of concerns over its safety, the amount of minocycline prescribed has fallen by about two thirds, while the overall volume of prescribing of all tetracyclines has increased by 10%. However, given that over 100,000 prescriptions for minocycline are still issued each year, is further action required in light of the adverse effect profile of the drug?

Doubts about the safety of minocycline started in the 1990s with reports of rare but serious and apparently idiosyncratic adverse effects that included hypersensitivity reactions of eosinophilia, pneumonitis and nephritis, autoimmune hepatitis and lupus erythematosus-like syndrome.5,6Such reactions seem to be more common with minocycline than with other tetracyclines.7 In addition, minocycline appears to be the only tetracycline that can cause potentially irreversible slate-grey pigmentation of the skin.

Source: BMJ